Merge pull request #2392 from daltonclaybrook/collection-alignment

New Rule - Collection Element Alignment

CHANGELOG.md

@@ -65,6 +65,11 @@
   [Marcelo Fabri](https://github.com/marcelofabri)
   [#1371](https://github.com/realm/SwiftLint/issues/1371)
 
+* Add `collection_alignment` opt-in rule to validate that all elements in a
+  collection literal are aligned vertically.  
+  [Dalton Claybrook](https://github.com/daltonclaybrook)
+  [#2326](https://github.com/realm/SwiftLint/issues/2326)
+
 #### Bug Fixes
 
 * Fix `comma` rule false positives on object literals (for example, images).  

Rules.md

@@ -11,6 +11,7 @@
 * [Closure End Indentation](#closure-end-indentation)
 * [Closure Parameter Position](#closure-parameter-position)
 * [Closure Spacing](#closure-spacing)
+* [Collection Element Alignment](#collection-element-alignment)
 * [Colon](#colon)
 * [Comma Spacing](#comma-spacing)
 * [Compiler Protocol Init](#compiler-protocol-init)
@@ -1705,6 +1706,129 @@ filter ↓{ sorted ↓{ $0 < $1}}
 
 
 
+## Collection Element Alignment
+
+Identifier | Enabled by default | Supports autocorrection | Kind | Analyzer | Minimum Swift Compiler Version
+--- | --- | --- | --- | --- | ---
+`collection_alignment` | Disabled | No | style | No | 3.0.0 
+
+All elements in a collection literal should be vertically aligned
+
+### Examples
+
+<details>
+<summary>Non Triggering Examples</summary>
+
+```swift
+doThings(arg: [
+    "foo": 1,
+    "bar": 2,
+    "fizz": 2,
+    "buzz": 2
+])
+```
+
+```swift
+let abc = [
+    "alpha": "a",
+    "beta": "b",
+    "gamma": "g",
+    "delta": "d",
+    "epsilon": "e"
+]
+```
+
+```swift
+let meals = [
+                "breakfast": "oatmeal",
+                "lunch": "sandwich",
+                "dinner": "burger"
+]
+```
+
+```swift
+let coordinates = [
+    CLLocationCoordinate2D(latitude: 0, longitude: 33),
+    CLLocationCoordinate2D(latitude: 0, longitude: 66),
+    CLLocationCoordinate2D(latitude: 0, longitude: 99)
+]
+```
+
+```swift
+var evenNumbers: Set<Int> = [
+    2,
+    4,
+    6
+]
+```
+
+```swift
+let abc = [1, 2, 3, 4]
+```
+
+```swift
+let abc = [
+    1, 2, 3, 4
+]
+```
+
+```swift
+let abc = [
+    "foo": "bar", "fizz": "buzz"
+]
+```
+
+</details>
+<details>
+<summary>Triggering Examples</summary>
+
+```swift
+doThings(arg: [
+    "foo": 1,
+    "bar": 2,
+   ↓"fizz": 2,
+   ↓"buzz": 2
+])
+```
+
+```swift
+let abc = [
+    "alpha": "a",
+     ↓"beta": "b",
+    "gamma": "g",
+    "delta": "d",
+  ↓"epsilon": "e"
+]
+```
+
+```swift
+let meals = [
+                "breakfast": "oatmeal",
+                "lunch": "sandwich",
+    ↓"dinner": "burger"
+]
+```
+
+```swift
+let coordinates = [
+    CLLocationCoordinate2D(latitude: 0, longitude: 33),
+        ↓CLLocationCoordinate2D(latitude: 0, longitude: 66),
+    CLLocationCoordinate2D(latitude: 0, longitude: 99)
+]
+```
+
+```swift
+var evenNumbers: Set<Int> = [
+    2,
+  ↓4,
+    6
+]
+```
+
+</details>
+
+
+
 ## Colon
 
 Identifier | Enabled by default | Supports autocorrection | Kind | Analyzer | Minimum Swift Compiler Version

Source/SwiftLintFramework/Models/MasterRuleList.swift

@@ -12,6 +12,7 @@ public let masterRuleList = RuleList(rules: [
     ClosureEndIndentationRule.self,
     ClosureParameterPositionRule.self,
     ClosureSpacingRule.self,
+    CollectionAlignmentRule.self,
     ColonRule.self,
     CommaRule.self,
     CompilerProtocolInitRule.self,

Source/SwiftLintFramework/Rules/RuleConfigurations/CollectionAlignmentConfiguration.swift

@@ -0,0 +1,28 @@
+public struct CollectionAlignmentConfiguration: RuleConfiguration, Equatable {
+    private(set) var severityConfiguration = SeverityConfiguration(.warning)
+    private(set) var alignColons = false
+
+    init() {}
+
+    public var consoleDescription: String {
+        return severityConfiguration.consoleDescription + ", align_colons: \(alignColons)"
+    }
+
+    public mutating func apply(configuration: Any) throws {
+        guard let configuration = configuration as? [String: Any] else {
+            throw ConfigurationError.unknownConfiguration
+        }
+
+        alignColons = configuration["align_colons"] as? Bool ?? false
+
+        if let severityString = configuration["severity"] as? String {
+            try severityConfiguration.apply(configuration: severityString)
+        }
+    }
+
+    public static func == (lhs: CollectionAlignmentConfiguration,
+                           rhs: CollectionAlignmentConfiguration) -> Bool {
+        return lhs.alignColons == rhs.alignColons &&
+            lhs.severityConfiguration == rhs.severityConfiguration
+    }
+}